rawsql-ts
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High-performance SQL parser and AST analyzer written in TypeScript. Provides fast parsing and advanced transformation capabilities.
77 lines • 3.22 kB
JavaScript
import { GroupByClause } from "../models/Clause";
import { TokenType } from "../models/Lexeme";
import { SqlTokenizer } from "./SqlTokenizer";
import { ValueParser } from "./ValueParser";
export class GroupByClauseParser {
// Parse SQL string to AST (was: parse)
static parse(query) {
const tokenizer = new SqlTokenizer(query); // Initialize tokenizer
const lexemes = tokenizer.readLexmes(); // Get tokens
// Parse
const result = this.parseFromLexeme(lexemes, 0);
// Error if there are remaining tokens
if (result.newIndex < lexemes.length) {
throw new Error(`Syntax error: Unexpected token "${lexemes[result.newIndex].value}" at position ${result.newIndex}. The GROUP BY clause is complete but there are additional tokens.`);
}
return result.value;
}
// Parse from lexeme array (was: parse)
static parseFromLexeme(lexemes, index) {
var _a;
let idx = index;
if (lexemes[idx].value !== 'group by') {
throw new Error(`Syntax error at position ${idx}: Expected 'GROUP BY' keyword but found "${lexemes[idx].value}". GROUP BY clauses must start with the GROUP BY keywords.`);
}
idx++;
let mode = null;
const modeCandidate = (_a = lexemes[idx]) === null || _a === void 0 ? void 0 : _a.value.toLowerCase();
if (modeCandidate === "all" || modeCandidate === "distinct") {
mode = modeCandidate;
idx++;
}
if (idx >= lexemes.length) {
if (mode === "all") {
return { value: new GroupByClause([], mode), newIndex: idx };
}
throw new Error(`Syntax error: Unexpected end of input after 'GROUP BY' keyword. The GROUP BY clause requires at least one expression to group by.`);
}
const items = [];
if (!this.isClauseBoundary(lexemes[idx])) {
const item = this.parseItem(lexemes, idx);
items.push(item.value);
idx = item.newIndex;
while (idx < lexemes.length && (lexemes[idx].type & TokenType.Comma)) {
idx++;
const item = this.parseItem(lexemes, idx);
items.push(item.value);
idx = item.newIndex;
}
}
if (items.length === 0 && mode !== "all") {
throw new Error(`Syntax error at position ${index}: No grouping expressions found. The GROUP BY clause requires at least one expression to group by.`);
}
else {
const clause = new GroupByClause(items, mode);
return { value: clause, newIndex: idx };
}
}
static isClauseBoundary(lexeme) {
return [
"having",
"window",
"order by",
"limit",
"offset",
"fetch",
"for",
].includes(lexeme.value);
}
static parseItem(lexemes, index) {
let idx = index;
const parsedValue = ValueParser.parseFromLexeme(lexemes, idx);
const value = parsedValue.value;
idx = parsedValue.newIndex;
return { value, newIndex: idx };
}
}
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